Railway-traffic-controlling apparatus



L. V. LEWIS TRAFFXC CONTRGLLING APPARATUS Ott 27, 1925' RAILWAY L. V. LEWIS Oct. 27 1925- RAILWAY TRAFFC CJNT'ROLLXNC' AP'FARATJS Filed April T8,

Patented Oct. 27, 1925.

UNITED STATES PATENT OFFICE.

LLOYD V. LEWIS, OF EDGEWOOD BOROUGH, PENNSYLVANIA, ASSIGNOR T0 THE UNION SWITCH & SIGNAL COMPANY, OF SWISSVALE, PENNSYLVANIA, A CORPORATION O'F PENNSYLVANIA.

RAILWAY-TRAFFIC-CONTBOLLING APPARATUS.

Application led April 28, 1924. Serial No. 709,398.

T 0 all whom it may concern.:

Be it known that I, LLOYD V. Lizwis, a citizen of the United States, residing at Edgewood Boi'ough. in the county of Allegheny and State of Pennsylvania, have invented certain new and useful Improvements in Railway-Traiic-Controlling Apparatus. of which the following is a specification.

Mv invention relates to railway tratiic controlling apparatus, and particularly to apparatus of the type comprising train-carried speed governing mechanism controlled by energy received inductively from the track- Iywill describe one form of apparatus embodying my invention and will theii point out the novel features thereof in claims.

In the accompanying drawings. Fig. 1 is a diagrammatic view showing one form of trackwav apparatus embodying my invention. Fig. 2 is a view partly diagrammatic and partly in section, showing one form of train-carried apparatus suitable for co-operation with the trackway apparatus shown in Fig. 1 and also embodying my invention.

Similar reference characters refer to similar parts in each of the views.

Referring first to Fig. 1, characters 1 and 1* designate the track rails of a railway along which tralic normally moves in the direction indicated by the arrow. These rails are divided by insulated joints 2. into a plurality of sections A-B, B-C. C-D, etc.

Each section is provided with a track circuit comprising a source of alternating track circuiti current connected across the rails at the exit end of the section, and a track relay receiving ener from the rails at the entrance end of the section. The immediate source of track circuit current for each section is a. transformer designated by the reference character 6 with a suitable exponent, the secondary of which transformer is connected across the rails of the section. Alternating current is supplied to the primary of each transformer 6 from a transformer 3 the reference through a pole-changer P, and the primary' rails of. the section in m of each transformer 3 is connected across a transmission line 5 which is constantly supplied with alternating current from a gen erator 4. Each pole-changer P isoperated in accordance with vence, as will be explained hereinafter.

traic conditions in ad' The` track relay for each section is designated by the reference character R with a suitable exponent, and in the form here shown each relay comprises two windings 'i' and 8. lVinding 7 is connected with the rails of the corresponding section while winding 8 is constantly supplied with alternating current of fixed relative polarity from the transmission line 5. The electrical connections between windings 8 and the transmission line are omitted from the drawing for the purpose of simplification. Each track relay comprises a contact 9 which is swung to the right or to the left according as the relay is energied by track circuit current of normal relative polarity or reverse relative polarity, that is, according as the polechanger P for the corresponding track circuit is in normal or reverse sition.

In the apparatus shown 1n Fig. 1, each track section is provided with a trackway signal designated by the reference character S with a suitable exponent, each ofl which signal is of the three-position semaphore type, arranged to indicate Proceed, Caution, and Stop. It is understood that these signals are controlled by the track relays R in any usual manner, but inasmuch as such control forms no part of my invention, the controlling circuits are omitted from the drawing. In accordance with usual practice each signal will indicate Stop when the associated track section is occupied, Caution when the associated track section is unoccupied and the section next in advance is occupied, and Proceed when the associated section and the section next in advance are both unoccupied.

In the arrangement of apparatus here shown, each pole-changer P is mechanically operated by the associated signal S and in such manner that the pole-changer is in normal position when the si al indicates Proceed and Caution, but in reverse position when the signal indicates Stop.

Means are also provided for supplying to each section a second alternating train governing current which ows through the ultiple. YFor this pu an impedance 12 is connected across the rails adjacent the entrance end of each section and a second impedance 13 is connected cross. the rails adjacent the exit endV the section..y This second current,

which I will term the loop current, is furnished by a transformer designated by the reference character E with a suitable exponent, the secondary windin 11 of which is connected with the midd e points of the two impedances 12 and 13 in the associated section by wires 98 and 99. The middle point of the primary 10 of each transformer E is connected with the lower arm of the adjacent pole-changer P, by a wire 97, and the two end terminals of the primary 10 are connected with the two fixed contact members respectively of contact 9 in the adjacent track relay R. The movable member of each contact 9 is connected with the upper arm of the associated pole-changer P by a wire 96. It follows that the relative polarity of the loop current for any given section is determined jointly by the position of the associated polechanger P and by the position of contact 9 of the track relay for the section next in advance.

As shown in the drawing, the section iinmediately to the right of point D 1s occupied by a train W, so that track rela RD is de-energized and signal SD indicates top. Pole-changer 1:D is in the reverse position, so that track circuit current of reverse relative polarity is supplied to the rails of section C'D. Inasmuch as track relay RD is de-energized, the primary circuit for transformer ED is open, so that the suppl of loop current to the rails of section D is discontinued. Track relay RC is enerized in reverse direction, so that signal Sc indicates Caution and pole-changer PC is in the normal position. Track circuit current of normal relative lpolarity is, therefore, supplied to the rails of section A1- ternating current of normal relative polarity is su plied to the upper half of the primary win ing 10 of transformer Ec, whereby loop current of what I will term reverse relative larity is supplied to the rails of section Track relay RB is energized in normal di-rection so that si al S indicates Proceed, and so it follows t at pole-changer PB is in the normal position and track circuitcurrent of normal relative polarity is supplied to the rails of section A-B. Alternati current of normal relative polarity is su plied to the lower half of the primary win ing 10 of transformer E", so that loop current of what I will term normal relative polarity is supplied to the rails of section A-B.

Referring now to Fig. 2, the train-carried mechanism comprises a pair of magnetizable cores 14 and 14 located in front of the forward axle and disposed above the two track rails 1 and 1, respectively. These cores are rovided with windings 16 and 16, whchPI will term track windings of the Also mounted on the train 'energized in the normal direction.

at a, convenient point is a pair of magnetizable cores 15 and 15 also disposed above t'he rails 1 and l, respectively, and provided with windings 17 and 17, which I will term the loop windings.

The track and loop windings control the supply of energy to the two stator windings 19 and 20, respectively, of an induction motor relay F, and suitable amplifying apparatus 18 is preferably introduced between each pair of windings and the relay. The relay F also comprises a rotor 2l controlling a plurality of contacts 22, '23, li and 25. The relay F and the pick-up apparatus for supplying energy thereto. is so arranged that when alternating track circuit and loop currents of normal relative polarity are flowing in the track rails the contacts 22, etc. are swung to the right, when the relative polarity of either of these currents is reversed the contacts are swung to the left, and when either alternating current is discontinued the relay contacts occupy intermediate or vertical positions.

The train is rovided with a signaling means G contro led by relay F and comprising three electric lamps A', R' and S', arranged when energized to indicate respectively Authorized speed. Restricted speed and Slow speed. When relay F is ener ized in normal direction the authorize speed lamp A is lighted by virtue of a circuit which passes from terminal B of a suitable source of current through contact 22, lamp A' and contact 23 to terminal O of the same source of current. When relay F is energized in the reverse direction, the restricted speed lamp R is lighted through a circuit similar to that for lamp A but including the left-hand points of contacts 22 and 23. When relay F is de-energized, the slow speed lamp S is lighted through a circuit which passes from terminal B through contact 24, lamp S, and contact 25 to terminal O.

The train is provided with speed goveruing apparatus which is controlled by an unlimited speed magnet 26 and a high speed magnet 26H. Magnet 26 is connected in multiple with the authorized speed lamp and so it is energized whenever relay l" is High speed magnet 26H is connected in multiple with the restricted speed lamp R. and so it is energized whenever relay F is energized in the reverse direction. Magnet 26U controls a valve 49 in such manner that this' valve occupies its upper position when the magnet is de-energized, and its lower position when the magnet is energized. Magnet 26 controls a valve 68 in a similar manner. The valves 49 and 68.control a relay valve mechanism 92 coixgris'- an unlimited speed/relay slide valve. ali-:ige high speed relayslidevalve'f-KPIQTBQ is provided with a speed governor' V comprising a centrifugal device T driven by a wheel of the train and operating a crosshead 93, which in turn coacts with a high speed valve '27, a low speed valve 2i-L. and a blow-down valve '28. The speed governor' V and the relay valve mechanism 9; co-operate to control a brake application valve Y comprising a slide valve 255 and a piston 36 provided with a restricted port 86a. 'hen the slide valve It?) is in the position shown in the drawing` it operates to prevent an automatic application ot the brakes. but when )this valve is shifted to the right it cuts ott' main reservoir pressure from the engineers valve M and causes an automaticapplication ot' the brakes through the medium of ports and pipes which are not shown in the drawing. Air pressure is normally supplied to the chamber above the slide valve ot valve Y from a source Z, and to the chamber at the right of the piston from the same source through port 3G in the piston. Slide valve and piston 36 are normally held in the inactive position, as shown by means of spring 9%. The mechanism also comprises the engineers brake valve M, and an engineers acknowledging valve H. and a release )ilot valve N. together with a timing valve k. and an acknowledging valve Q.

The operation of the apparatus shown in Fig. 2. as the train passes along the stretch ot' track shown in Fig. 1. is as follows:

Assuming that the train occupies section A\--B, it will be observed thatl track circuit current and loop current of normal relative polarity are supplied to the train so that relay l" is energized in the normal direction. the authorized lamp A' is lighted, and the unlimited speed magnet QGU is energized. A\ir pressure is supplied to the chamber above slide valves KU and KH from a source Z through pipes 37. 38 and 2&9. and to the chamber at the right of piston 5l from the same sourcethrongh branch pipe 4S. valve 45) and pipe K0. to equalize the pressure on both sides of piston 5l. The uulimited speed relay valve KU is then held in its left-hand position by means ot' spring ltltl. so that air pressure from the chamber above KU passes through portJ 40 and pipe 42 to reservoir 33. and through pipe 42% to the chamber above diaphragm 4t of timing valve X. causing this valve to assume its lower position. Air pressure is then supplied from source Z through pipes 37 and 37a. valve 45 and pipe 4G to the chamber at the left ot' piston 4T of valve KU. to equalize the. pressure on both sides of piston t?. The high speed relay valve KH is held in its right-hand position by means of spring lOl. Since pipe 63 is blanked at cavity 64 in valve KU, there is no provision for exhausting air from the chamber at the right of piston 36 of the brake application valve Y, so that regardless ot the speed ot the train, this valve will remain in normal position. thereby preventing an automatic application ot' thi` brakes. ln other words.

the train can then make any speed ot' which it is capable. -\n acknowledging reservoir 3J( is opened to atmosphere through ports .'if) and 5S in the acknowledging valve Q. pipe Tl, pipe 5o. and port 0l in relay valve K".

-\s thc train enters `section l-C` the rela. tive polarity ot' the current supplied to winding 22() otl relay l'` is reversed. so that this relay reverses. thereby extinguishing the authorized speed lamp and lighting the restricted speed lamp R. .\t the same time the unlimited speed magnet :26" becomes cle-energized and the high speed magnet 26H becomes energized. The consequent reversal ot' valve t0 connects the chamber ot` piston 5t with atmosphere through pipe 5U. valve 49 and exhaust port G1. so that the unlimited speed relay valve KU moves to the right. Timing valve X and consequently relay valve KH remain unchanged in position because the chamber above diaphragm L-l is now supplied with air pressure from source Z through pipes 3T. 38 and 4S. valve G8 reversed. pipe 6T. cavity GG of K" reversed. pipes 4'2 and 43 to the chamber above it The pressure existing on the right-hand face ot' piston 36 in the `brake application valve Y is now exposed to the high speed governor valve 2T, through pipes 5;. .74 and (33. cavity G4 and pipe (33. If the speed ot the train is above a given high value, such as G5 miles per hour. valve 2T is opened by stem 29 on crosshead 93. so that the brake application valve Y is shifted to the right. thereby causing an automatic application oz' the brakes. On the other hand. it' tht` speed of the train is below 65 miles per hour. valve 2T is closed. so that no automatic brake application occurs.

Assuming that the speed ot' tht` train is above the given high vahu` on entering .sez-- tion B-C, so that an automatic brake application occurs. the train will be brought to a full stop provided the engineer takes uo action. The reason t'or this is that as sooo as brake application valve Y is shifted to the right. a path is opened from the chamber of piston 9,6. through pipes 52 and 513. cavity S0 in slide valve 35. pipe Sl. valve S2 and exhaust port S3 to atmosphere. so that the brake appli ation valve remains in applying position, even though the exhaust path through valve 2T becomesl closed as soon as the speed is reduced below the given high value. Valve 82 of the release pilot valve is held in the position shown by air from main reservoir through pipe 86. brake valve chamber 87, port 88. and pipe 84 to the chamber below piston 85 of valve N. In orderl to release the brakes the speed must be reduced so that valve '2TH is closed. and the engineer' lNI) Cil

must shil't his brake valve )I to the lap position. thereby connecting the lower piston chamber of the release pilot valve with atmosphere through pipe Si, cavity S9 and exhaust port 90. whereupon the valve 82 closes. thereby allowing pressure to build up on the right-hand face of piston 36 through the i'etricted port'364. As soon as this pressure builds up to a given value` determined by the spring 94. the slide valve 35 will be restored to its initial position, whereupon the engineer may release the brakes by the ,-ustomary manipulation ot' valve M, and the train may then proceed.

As the train enters section C-D, relay F will become ile-energized owing to the fact that the supply of loop current to the rails of this section has been discontinued. The slow speed lamp S will then become lighted and the high speed magnet 26H will be deenergized. The timing reservoir and the upper diaphragm chamber of the timing valve X are now connected to blow-down valve 28, through pipe 42. cavity 66, pipe 6T,

valve 68 and pipe 62. Blow-down valve 2S- has a fixed small orifice 102 opening directly to atmosphere, and a larger variable orilice 103 which is opened by the movement ot the piston of this valve by stop 31 on crosshead 93, by an amount substantially proportional to the train speed` so that the pressure in reservoir 33 and above diaphragm l-t will be reduced at a rate which is substantially' proportional to the speed of the train. That is, at comparatively high speeds the pressure will be reduced in a few seconds to such value that valve X will reverse, whereas at relatively low speeds this reduction ot pressure will not be accomplished for approximately 3() seconds. As soon as the valve X reverses, the pressure in the lefthand piston chamber of valve K will be exhausted to atmosphere through pipe 16, valve 1.3 and exhaust port 69. whereupon the high speed relay valve KH will be. shifted to the left. Assuming that the engineer has not acknowledged the caution indication at the entrance to the block C-D, the right-hand piston chamber of the brake application valve Y will be connected with the empty acknowledgment reservoir 34 through pipes 52. 5+ and 55, port 91, pipe T0, check valve 3;. pipe 71 and ports 58 and 59 of valve Q to reservoir 34. The brake application valve Y will then shift to the right. thereby applying the brakes regardless of the speed at which the train is traveling. It, however, the engineer acknowledges the caution signal prior to the reversal of valve KH, this automatic brake a plication will be prevented if the speed of tievtrain is below a given low value. such as 15 miles per hour. The acknowledving'apparatus is as follows: When the hande of the acknowledging valve H is in the position shown in the drawing, a

reservoir iis charged with pressure from source Z through cavity Tl and pipe T6. 'l'o acknowledge a signal, the engineer reverses the handle of valve H. so that reservoir Ti' is disconnected from source Z and its pressure flows through pipe T6. cavity Tt and pipe TT to the lower piston chamber ot' valve Q. thereby lifting piston T8 and valve i3() to close portl 5S and to open valve 05, thereby permitting pressure to pass from pipe 3S. through pipe 57, valve 95 and port 5!) to reservoir. 31, so that when valve Q returns to its original position, which will occur after an interval ot approximately l0 seconds, the pressure in reservoir IH will be applied to pipe 56. and, consequently. to the upper portion of the check valve 3'2. lYheu. therefore` the relay valve K reverses, the pressure in the right-hand piston chamber of valve Y will not. be reduced suliciently to cause piston 36 to move and so the brakes will not be applied unless the low speed valve 2T is open. This low speed valve is opened by stem 30 in crosshead 93 if the speed of the train is above a given low value` such as 15 miles per hour. The train may there.q fore proceed through section C-D without incurring an automatic application of the brakes. provided that the speed does not rise above 15 miles per hour, and the train may. furthermore, proceed into the section at the right of D under the same restriction.

One important feature of my invention is that comparatively short sections may be employed, permitting close spacing of trainsl in congested territory. This is because means are provided for insuring that the train speed does not exceed a predetermined value at the entrance to a caution section. The stopping distance of trains at this speed` which may be determined by tests, furnishes a basis for determining the safe minimum length of section, and the sections can therefore be safely made much shorter than would be the case if it were necessary to base the section lengths upon the assumed stopping distances at the maximum speed that any train would be capable of making. This4 latter arrangement would be undesirable because the sections would become so long that the capacity of the road would be unduly restricted. Another feature of mv invention is that the capacity of the road is less restricted than when a continuously eiiectivc high speed limit is employed, which limit. if based upon desirable section lengths. must be less than can safely be permitted when a train has a clear track ahead for two or more sections, and the signals and track are visible for long distances in advance.

One advantage of my invention is that it imposes no restrictions and permits the train to travel at any desired speed until it enters the second section in the rear of an occupied section, whereupon the speed must be relll) duced to such a value as to insure that it may be stopped, or brought to a predetermined low speed within the length of the section in the rear of the occupied section.

Although I have herein shown and described only one form of apparatus embodying my invention, it is understood that various changes and modifications may be made therein within the scope ot' the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

l. In combination, a stretch of railway track divided into sections, means for supplying two alternating currents to the rails of each section, means responsive to the presence of a train in any one section for discontinuing the supply of one said current from the section in the rear and reversing the relative polarity of one said current in the second section in the rear; and train carried apparatus controlled by said currents and operating to enforce a high speed limit when both currents are present and one is of reverse relative polarity and a low speed limit when the supply ot' either current is discontinued, said apparatus operating to permit unlimited speed when both of said currents are present and both are of normal relative polarity.

2. In combination, a stretch of railway track divided into sections, means for supplying two alternating currents to the rails of each section one of which Hows through the two rails in series and the other of which ilows through the two rails in multiple,

means responsive to the presence of a train in any one section for discontinuing the supply of one said current from the section in the rear and reversing the relative polarity of one said current in the second section in the rear; and train carried apparatus controlled by said currents and operating to enforce a high speed limit when both currents are present and one is of reverse relative polarity and a low speed limit when the supply of either current is discontinued, said apparatus operating to permit unlimited speed when both ot' said currents are present and both are of normal relative polarity.

3. In combination, a stretch of .railway track divided into sections; means tor aen section for supplying two alternating currents of normal relative polarity to the rails when the two sections in advance are unoccupied, two alternating currents of relative polarities opposite to each other when the second section in advance is occupied and the intervening section is unoccupied. and only one alternating current when me section immediately in advance is occupied; and train carried apparatus controlled by said currents and operating to enforce a high speed limit when both currents are present and one is of reverse relative polarity and a. low speed limit when the supply of either current is discontinued, said apparatus o erating to permit unlimited speed when bot of said currents are present and both are of normal relative polarity.

In testimony whereof I aliix my silgnature.

LLOYD V. LEVIS. 

